Steam for Linux changes my mouse cursor into a a very ugly generic one in GTK apps -- and this change persists even after I close Steam. Specifically the ugly cursor appears when opening context menus. Illustration: http://www.youtube.com/watch?v=r0GGyA3p_GA.

Can I prevent it doing that? I tried resetting the cursor in KDE control panel, but it didn't work. Perhaps Stem is exposing a bug in X / GTK?